OpenEuphoria

1. Procedural design patterns?

• Posted by TheresNoTime Sep 26, 2013
• 2127 views

I recently became interested in object-oriented programming, because I began to sink in my own code. By studying design patterns, I came across the sentence:

Maybe my problem is not the use of improper language, but a improper use of language? Do you know any more patterns that are suitable for Euphoria?

I tried to find this information, but stupid Google feeds me links about OOP. Maybe you know some old book? Please, do not advise books by Donald Knuth! :)

3. Re: Procedural design patterns?

• Posted by TheresNoTime Sep 26, 2013
• 2057 views

Yes, this is the most likely option. Sometimes, when I see that I can not do something, I start looking for a new language, rather than figure out how to do it in the old language. However, I am embarrassed that such situations occur more and more frequently with increasing the size of the program.

P.S. For example, how to implement CQRS in Euphoria? I can not figure out how this can be done without the OOP.

5. Re: Procedural design patterns?

• Posted by TheresNoTime Sep 26, 2013
• 2077 views

integer x = 0 
function value() 
  return x 
end function 
 
procedure increment_x() 
  x = x + 1 
end procedure 

Of course, I did not mean such a trivial example. Let x is the level of force of an object in the game (the hero, the monsters, the boss). Pseudo-OOP-Eu:

hero = clone(person) 
hero.lifepoints = 100 
for i = 1 to 100 do 
  monsters[i] = clone(hero) 
end for 
boss = clone(hero) 
boss.lifepoints *= 10 
--------------------- 
if monsters.count = 0 then 
  attack_boss() 
  if boss.lifepoints = 0 then 
    puts(1, "You saves FairyLand!") 
  else 
    puts(1, "Boss eats you! :(") 
  end if 
end if 

How to automate reading and writing multiple parameters of the same type? Use a sequence where the first integer is hero's lifepoints, the next 100 - monsters' lifepoints, and 102nd is the boss?

sequence LifePoints = repeat(100, 101) & 1000 
 
export fuction hit(integer who) 
  LifePoints[who] -= 1 
end function 

Thank you. I'd rather look into the OOP.

7. Re: Procedural design patterns?

• Posted by useless_ Sep 26, 2013
• 2093 views

You could "wrap" the characters in a timeslice using task.e, this would reuse the same code for each character, and keep separate variables for each. Of course you'll need task messaging if you want the monster char to tell the human he just got bit, where, and how much. Or tell the sword object that it's length is now half. I quit working on it when someone else began working on it, and made my code useless.

useless

9. Re: Procedural design patterns?

• Posted by jaygade Sep 26, 2013
• 2049 views

Doing what you want to do in a pseudo-object-oriented fashion in Euphoria really shouldn't be that difficult, the main differences will be that you have to do some manual bookkeeping (keeping track of object instances), you have to manually specify a "this" parameter, and that you can't use dot notation.

• Create a file for your class. The filename and default namespace is your class name. Many true object-oriented languages require this as well.
• Create your class variables. You will need to keep your instances either in a simple list, or you could use more complex data structures such as stack, map, whatever. Heck, you could probably even use EDS if you needed to be able to save and restore your state.
• Create your object data type and any enums or constants required to be used with them.
• Create your class methods, such as "new", "delete", or any others which work on the class as a whole. These can be procedures or functions as required.
• Create your instance methods, such as getters and setters and "copy", "clone", comparisons, etc. as required.
  • Instance methods should take at least one parameter corresponding to "this" object -- usually some key returned by the "new" method. This is your key into your object list (whether a simple list or whatever).
  • Some instance methods may take an entire object representation to work on, but this should be avoided if possible.

For inheritance, you just include the parent classes/files in your new class/file. Prototyping is kind of built-in, you can get pretty involved with copying classes, objects, and methods if you need to.

Avoid exposing any variables outside of your class file -- make them all accessible and modifiable by getters/setters and other methods. At the most, a particular method may return an object representation as a sequence or may take an object represented as a sequence as an input parameter, but again that should be relatively rare.

Note: I've never actually done any of this, but Euphoria has the tools built-in to do it.

11. Re: Procedural design patterns?

• Posted by ghaberek (admin) Sep 26, 2013
• 2024 views

I've done this before and it can work pretty well. Here are some points from my experience.

• Always declare one class per file, each with a matching namespace.
• You can wrap multiple classes into a single include using public include.
• You can use a map object as your base "type" for all classes.
• Create setters and getters for all of your properties and store the values directly in the map object.
• You can inherit from classes by public include-ing it in the new class file.
• Parent class methods have to be generic enough to accept any child class.
• Otherwise, override the method in the child class directly, and then call the "base" class method from there.
• Use the unit testing framework to test all of your classes!

I've put together a brief example here: http://openeuphoria.org/pastey/231.wc

-Greg